Acceleration of gelatinization of cellulose nitrate



Patented Aug. 30, 1927.

UNITED STATES 1,540,712 PATENT OFFICE.

ROBERT C. MORAN, 0F WOODBURY, NEW JERSEY, ASSIGNOR T0 E. I. DU PONT DE NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELA:

WARE.

ACCELERATION OF GELATINIZATION OF GELIiULOSE NITRATE.

No Drawing.

This invention relates to the acceleration of the gelatinization of mixtures of cellulose nitric esters with liquid nitric esters, particularly, glyceryl trinitrate and its mixtures with freezing-point depressants such as nitrated diglycerine, nitrated sugars, etc.

In the manufacture of non-solvent gelatinized nitro-glycerine explosives, such as blasting gelatine and gelatine dynamite, the mixture of nitrocellulose and vnitrog'rlycerine is gelatinized previous tothe addition of the rest of the ingredients. The rate of gelatinization of such-a mixture is dependent for the most-part upon three factors; first, the temperature at. which the gelatinization is effected, second, the quantity and quality of the nitrocellulose used, and, third, whether the nitroglycerine is straight glyceryl trinitrate or a mixture he eof with a freezing-point depressant. Each of these factors requires careful control. measures in order to insure satisfactory rapidity of gelatinization.

I have discoveredthat the rate of gela- 7 tinization of cellulose nitric esters with liquid nitric esters, particularly glyceryl trinitrate and its mixtures with freezing-point depressants, can be accelerated by means of small amounts of aliphatic alcohols which are soluble in glyceryl trinitrate. This discovery makes it possible to exert a more or less arbitrary control over the rate of gelatinization of such mixtures, to shorten the time of manufacture and to overcome one of the difficulties encountered in the manufacture of low freezing gelatine dynamites containing for example nitrated polymerized glycerine as a freezing-point depressant of trinitroglycerine.

As representative accelerators of the monohydric alcohol class, I mention methyl and ethyl alcohols, and as examples of accelerators of the polyhydric alcohol class there may be mentioned ethylene and trimethylene glycols. I prefer to use the dihydric alcohols, and particularly the lower glycols, that is the glycols having from two to four carbon atoms, (1) because of their solubility values in the glyceryl trinitrate or other liquid nitric ester .which is to be gelatinized with the nitrocellulose, and (2) because of their low volatility as compared with methyl and ethyl alcohols. The butylene glycols (for instance the alpha or Application filed June 19, 1924. Serial No. 721,004.

beta isomers) are capable of effecting an acceleration ot' the same. order as that of theother glycols above mentioned. Glycerol, apparently because .of its low solubility in glyceryl trinitrate, exerts little, if any acce erating action on the gelatinization of a mixture of glyceryl trinitrate and nitrocellulose. F

The quantity of the above accelerators re- I quired to bring about a decided effect in the rate of gelatinization of mixtures of cellulose nitric esters with liquid nitric esters as,

' for instance, glyceryl trinitrate, straight or in mixture with freezing-point depressants,

very small. For example, 1% ethyl alcohol, when added to a mixture of 8% nitrocellulose and 92% low-freezing nitroglycerine, while maintaining the resulting mixture at a temperature between F. and

F. reduced the time required for gelatinization from 12 minutes to 5 minutes; 1%

ethylene glycol reduced the time from 12 minutes to 5% minutes; and 1% trimethylene glycol from 12 minutes to 6 minutes, other conditions remaining the same. While the proportion of accelerator used may be 1% or more based upon the weight of liquid nitric'ester to be gelatinized, I prefer to use substantially less than 1% of the accelerator-for example from carrying inorganic salt such as sodium or ammonium nitrate, a combustible non-explosive material such as corn meal or Woodmeal, and in certain cases various other substances su'ch as nitrohydrocarbons, sulphur,

chalk, sodium chloride, etc., depending upon the kind of blasting operation for which the high explosive is being made.

I claim: 4

1. The process of accelerating the gelatinization of cellulose nitrate with a liquid nitric ester which comprises mixing said substances in the presence of an aliphatic alcohol that has a greater solubility in said liquid nitric ester than has glycerol, the quantity of said alcohol being sufliciently small so as to produce substantially no effect upon the sensitiveness of the mixture a an explosive. 2. The process of accelerating the gelatinization of cellulose nitrate with a liquid nitric ester which comprises mixing said substances in the presence of a polyhydric aliphatic alcohol that has a greater solubility in said liquid nitric ester than has glycerol.

3. The process of accelerating the gelatinization of cellulose nitrate with a liquid nitric ester which comprises mixing said substances in the presence of a polyhydric alcohol containing from two to four carbon atoms that has a greater solubility in said "liquid' nitric ester than has glycerol.

4:. The rocess of accelerating the gelatinizationof cellulose nitrate with a liquid -nitric ester which comprises mixing said substances in the resence of a dihydric alcohol containing rom two to four carbon atoms.

5. The process of accelerating. the gelatinization of cellulose nitrate with a liquid nitric ester which comprises mixing said substances in the presence of trimethylene glycol. Y I

6. A process as set forth inclaim 1 in i which the proportion of alcohol is not more than about 1% based on the weight of liquid nitric ester present.

. 7. A process as set forth in claim 2 in whichthe proportion of alcohol is not more than about 1% based on the weight of liquid nitric ester present.

8. A process as set forth in claim 3 in which the proportion of alcohol is not more than about 1% based on the weight of liquid nitric ester present.

9. A process as set forth in-claim 4 in which the proportion of alcohol is not: more than about 1% based on the weight of liquid nitric ester present.

10. A processes set forth in claim 5 in which the proportion of glycol used is not more than about 1% based on the weight of liquid nitric ester present.

11. A process as set forth in claim 1 in which the liquid nitric ester comprises glycl eryl trinitrate and a freezing point depressant.

13. A process as set forth in claim 3 in which the liquid nitric ester comprises glyceryl trinitrate.

14. A process as set forth in claim 3 in which the liquid nitric ester compiises glyceryl trinitrate and the nitrated derivative ofa polyhydroxy aliphatic compound containing more than three hydroxyl groups.

15. A process as set forth in claim 4 in which the liquid nitric ester comprises glyceryl trinitrate and a freezing-point depressant.

16. The process of making a highexploslve composltion whlch comprises gelatinizing a mixture of cellulose nitrate, nitroglycerine and a freezing-point depressant in the .so as to produce substantially no effect upon the sensitiveness of the mixture as an explosive; r

18. A process as set forth'in claim 16 in which the alcohol is a glycol having between one and five carbon atoms.

19. A composition as set forth in claim 17 in which the alcohol is a olyhydric. alcohol containing from two to our carbon atoms.

20. A high explosive composition comprising a gelatinized mixture of cellulose nitrate and nitroglycerine and containing a glycol having from two to four carbon atoms.

21. A high explosive composition comprising a gelatinized mixture of cellulose nitrate and nitroglycerine and containing not more that 1% ofa glycol having from two to four carbon atoms.

which the liquid nitric ester comprises glyc- In testimony whereof I atfix my signature.

' eryl trinitrate;

12. A process as set forth in claim 1 in ROBERT o. MORAN. 

